Genome-wide association study of heat stress response inBos taurus

Heat stress is a major challenge in cattle production, affecting animal welfare, productivity, and economic viability of the industry. In this study, we conducted a genome-wide association study (GWAS) to identify genetic markers associated with tolerance to heat stress in Chinese Holstein cattle. We genotyped 68 cows using Illumina 150K Bovine BeadChip microarray and analysed 112,081 single nucleotide polymorphisms using a linear model-based GWAS approach. We identified 17 SNPs distributed on three chromosomes that showed statistically significant associations with tolerance to heat stress in Chinese Holstein cattle. Five of them were located in introns of two genes, PDZRN4 and PRKG1. PDZRN4 is involved in protein degradation pathways, while PRKG1 encodes a protein kinase involved in smooth muscle relaxation and blood vessel dilation. Our findings highlight the potential importance of PDZRN4 and PRKG1 in heat stress tolerance in cattle and provide valuable genetic markers for further research and breeding programmes aimed at improving the tolerance to heat stress in Holstein cattle. However, more studies are needed to elucidate the exact mechanisms by which these SNPs contribute to tolerance to heat stress and their potential implications for practical cattle breeding strategies. Author summary Heat stress is a critical challenge in cattle production, leading to reduced productivity and increased mortality rates. In our study, we conducted a genome-wide association study (GWAS) to identify genetic markers associated with indicators of tolerance to heat stress in cattle. We found significant associations between indicators of heat stress tolerance and specific single nucleotide polymorphisms (SNPs) located in two genes, PDZRN4 and PRKG1 . These genes are known to play roles in protein degradation pathways and smooth muscle relaxation, respectively, and have previously been implicated in physiological responses to heat stress in other species. Our findings provide insight into the genetic mechanisms underlying heat stress tolerance in cattle and could potentially be used in genomic selection programmes aimed at improving heat stress tolerance in cattle populations. More research is needed to elucidate the functional importance of these SNPs and their potential applications in cattle breeding programmes.